WinRT: Adopt new event dispatcher approach for WinRT plugin

Change-Id: I5605cbe926b57b981071d71187aca6af5d2e6269
Reviewed-by: Andrew Knight <andrew.knight@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
WinRT: Improve orientation handling

Support setting the update mask.

Change-Id: I88f4dddd9af5203ec47c70ad3381436caf140fef
Reviewed-by: Andrew Knight <andrew.knight@digia.com>